Cloud Prov And Virtualization Flashcards
What are some of the consequences of not having virtualization?
The software is strongly linked/related with the hardware, therefore, moving/changing in application is not an easy task
Low Flexibility
What are some of the consequences of the virtualization?
Hardware independence, software/hardware are no longer strongly related
High flexibility, thanks to pre built virtual machines
OS, and applications can be handled as a single entity
What are the impacts of the virtualization on the evolution of IT systems?
Server consolidation
Cloud computing
What are the reasons for server consolidation as an impact of virtualization on the evolution of vital systems?
Consolidation management, migration from physical to virtual machines. It is possible to move the virtual machines without interrupting the application running inside. It is also possible to automatically balance the workload, according to set limits and guarantees.
Servers and applications are protected against components and system failure
Different OS can run on the same hardware
Higher hardware utilization
What are some of the reasons for the cloud computing to be the consequence of the virtualization in the development of IT systems?
Cloud computing is a model for enabling convenient, on demand network access to a shared pool of configurable computing resources (network, servers, storage, applications, service) that can be rapidly provision and released with minimal management effort or service provider interaction
What are the three main services provided by cloud?
Cloud application, cloud software environment, and cloud software infrastructure (computational resources, storage, communications)
Define the cloud application layer
SaaS
User access the services provided by the layer through web portal and are sometimes required to pay fees to use them
Define the cloud software environmental layer
PaaS
Users are application developers
Providers supply developers, with a programming, language level environment with a well-defined API
Define the cloud software infrastructure layer
IaaS: Computational
DaaS: Storage
CaaS: Communications
Provides resources to the higher level layers (software and software environment)
What are the advantages and disadvantages of virtual machines?
Advantages, flexibility, and super user
Disadvantages, performance interference, and inability to provide strong warrantees about SLAs
Define the DaaS
Data as a service allow the user to store their data at remote discs and access data anytime from any place
Define the CaaS
Communication as a service provides communication capabilities, and network securities, dynamic provision of virtual overlay for traffic, isolation or dedicated bandwidth, guaranteed message delay, communication, encryption, and network monitoring
What are the types of clouds?
Private, community, hybrid, public
What are some characteristics of public clouds?
Large scale infrastructure available on a rental basis
Fully customer self service, service level agreements are advertised, resources are rented via web services
Accountability is e-commerce based
What are some characteristics of pirate clouds?
They are internally managed data centers
The organization set up a virtualization environment on its own servers
What are some characteristics of community clouds?
They are single cloud managed by several federated organizations
Technically similar to private cloud
Hosted locally or externally
Define some characteristics of hybrid clouds
Hybrid already combination of any of the other types
How is cloud implemented?
Through virtualization, hardware resources (CPU, run, ECC…) are partitioned and shared along multiple virtual machines
What is the VMM?
Virtual machine monitor governs the access to the physical resources among running VM’s
What is the level of ISA in a layered execution model? What is its importance?
Level two
It marks the division between hardware and software
What are the two different types of ISA?
User ISA, aspects of the ISA that are visible to an application program. When application interacts with the hardware, user ISA is used.
System ISA, aspects visible to supervisor software (I. E., the OS) which is responsible for managing hardware resources. When the OS interacts with the hardware, system ISA is used.
What is the level of the ABI in the layered execution model? What does ABI stand for?
Application binary interface corresponds to level three in the layered execution model
What are the two different interfaces of ABIs?
The two interfaces in the application binary interface are the user ISA and the system call (which are calls that allow programs to interact with shared hardware resources, indirectly by OS)
What is a virtual machine?
It is a logical abstraction able to provide a virtualized execution environment
What are the tasks of a VM?
To map virtual resources or states to corresponding physical ones
To use physical machining instructions/calls to execute the virtual ones
What are the two types of virtual machines?
Process VM’s and system VMs
What are the characteristics of process VM’s?
The runtime software supports the levels 0-3 off the architecture
Virtualization software replaced at the ABI interface, on top of the OS/hardware combination
The virtualizing software emulates both user level instructions and operating system calls
Define system VM’s
The VMM support the level 0–2 of the architecture
Provide a complete system environments that can support an operating system (potentially with many user processes)
Provides operating system running in it access to underlying hardware resources
Virtualizing software placed between hardware and software (emulates the ISA interface seen by software )
What are the definitions for host and guest?
Host is the underlying platform supporting the environment/system
Guest is the software that runs in the VM environment as the guest
How does virtualization is implemented?
Given a typical layered architecture of a system by adding layers between execution stock layers
Depending on where the layer is placed, we will be taking different types of virtualization what are them?
Hardware level of virtualization, application level virtualization, and system level virtualization
Define the hardware level virtualization
Virtualization layer placed between hardware and OS
Interface seen by application might be different from the physical one
Defined the application level virtualization
If vitalization layer is placed between the OS and some applications
Provides the same interface to the applications
Application run in their environment, independently from OS
Define System level of vitalization
Vitalization layer provides the interface of a physical machine to a secondary OS and a set of application running in it, allowing them to run onto top of an existing OS
Placed between the system OS and other Os
Enable several OSs to run on a single hardware
Define System level of vitalization
Vitalization layer provides the interface of a physical machine to a secondary OS and a set of application running in it, allowing them to run onto top of an existing OS
Placed between the system OS and other Os
Enable several OSs to run on a single hardware
What are the properties of vitalization technologies?
Partitioning, execution of multiple OS on a single physical machine
Isolation
Encapsulation
Hardware independence
What are VMMs
Virtual machine manager, virtual machine monitor, or hypervisor are application that manages the virtual machines, mediate access to the hardware resources on the physical host system, and intercept and handles any privileged or protected instructions issued by the virtual machines
What are the hypervisor types?
Type one and two
Define the type one hyper visor
Type one or bare metal takes direct control of the hardware
There are two of them monolithic and microkernel
What are monolithic hypervisor and they are advantages and disadvantages?
Device drivers run within the hyper visor
It is better for performance and isolation
But it can run only on the hardware for which the hypervisor has drivers
What are microkernel hypervisor and their advantages and disadvantages?
Device drivers run within a service virtual machine
Advantages: Smaller hypervisors and leverage driver ecosystem of an existing, can third-party driver
Disadvantages:
What are the type two hypervisors?
They resigned within a host operating system.
The host OS controls the hardware of the system
What are the advantages and disadvantages of the type two hyper visors?
They are more flexible in terms of underlying hardware
They are simpler to manage and configure
The host OS might consume a non-negligible set of physical resources
What are the ways we can implement a system level vitalization
Paravirtualization and full virtualization
Define full virtualization
It provides a complete simulation of the underlying hardware
What are the advantages and disadvantages of full virtualization
Advantages:
Running unmodified OS
Complete isolation
Disadvantages:
Performance
Hyper visor mediation
Not every architecture
Define paravirtualization
Guest OS and VMM collaborates. VMM present to VM an interface similar but not identical to that off the underlying hardware.
What are the advantages and disadvantages of paravirtualization
Simpler VMM
Higher performance
Only modify guest OS
What are containers?
Containers are pre-configured packages, with everything you need to execute a code in the target machine
What is the main difference between VM and containers?
The main difference is that the containers share the host system kernel with other containers
What are the main advantages of containers?
The main advantages of containers is that their behavior is predictable, repeatable and mutable
